Myanmar's president has called for the evacuation of low-lying areas in the country's Irrawaddy delta region as massive flooding across the country continues to affect tens of thousands of people.

In a message broadcast Thursday, President Thein Sein said areas near the Irrawaddy at risk as the river rises "above [the] danger level."

About 6.2 million people live in the region, an area where the Irrawaddy and other rivers branch out into a delta leading to the sea.

The Ministry of Social Welfare, Relief and Resettlement said flooding triggered last week by heavy monsoon rains had killed at least 81 people and affected more than 250,000.

Four areas have been declared disaster zones with widespread flooding.

In Kuala Lumpur on Thursday, U.S. Secretary of State John Kerry said Washington would provide $600,000 in aid to help flood victims in Myanmar. Japan has pledged $150,000 in aid, while Vietnam is providing clean water worth $20,000.

Aid groups and volunteers have told the VOA Burmese service that relief workers are struggling to reach some hard-hit areas. The U.N. Office of Coordination of Humanitarian Assistance in Yangon has said the agency is trying to gain access to the affected areas.

Myanmar opposition leader Aung San Suu Kyi on Thursday posted a video on Facebook in which she appealed for more international help, emphasizing this year's monsoon season is not over yet.

She also expressed concern that the massive flooding in much of the country might be used as a pretext to undermine November's general election.

The Nobel Peace Prize laureate drew a parallel with a referendum, carried out under military rule in 2008, that brought in the current much-maligned constitution.

The 2008 voting took place during widespread chaos following Cyclone Nargis, which killed an estimated 140,000 people.

According to official results, the charter was overwhelmingly confirmed. But many reports cast doubt on the fairness of the vote and the results. The constitution was drafted under military supervision and enshrines its dominance in government, making substantial democratic reforms difficult to achieve.